Tool for treating ophthalmic lenses and process of making same



Nov. 29, 1927. 1,651,181

- L. w. BUGBEE ET AL TOOL FOR TREATING OPHTHALMIC LENSES AND PROCESS OF MAKING SAME Original Filed Dec. 6, 1924 4 I 1' I I IN! 'ENTORJ. Luc/mv W 30655:. Lawn/v m 306555, Jir.

A TTORNEY5.

Patent ed Nov. 29, 1927.

UNITED STATES 1,651,181 PATENT OFFICE.

LUCIAN 'W.'BUGBEE AND 'LUGIAN BUGIBEE, JR., OF INDIANAPOLIS, INDIANA, AS-

SIGNORS, BY MESNE ASSIGNMENTS, TO CONTINENTAL OPTICAL CORPORATION, OF NEW YORK, N. Y., CORPORATION OF DELAWARE.

'rooL ron'rnnn'rmc orn'rnannrronnnsns AND rnocnss or MAKING snmi.

s Original application filed December 6, 1924; Serial No. 754,843. Divided andvthis application filed November 24, 1925. Serial No. 71,258.

This-invention consists of an improved tool for polishing or fine grinding and generating the surface of an ophthalmic lens and the process of making such tool.

5 The object of the invention is to improveas well as cheapen and simplify the production of tools for fine grinding and polishing ophthalmic lenses. This process has been invented in connection with the develop- 1 ment of machines for generating surfaces,

shaping the operative surface of such tool on the surface of the lens blank which is to be fine ground or polished. This is done by placin on the lens blank which is to be 2 groun a sheet of lead or other flexible finegrinding-or polishing material, coating the tool holder with cement and pressing the same in engagement coaxially with the layer A of flexible material on the lens to be ground 80 or polished. This will cause said grinding or polishing sheet to adhere to the tool and thus shape the grindin face thereof, which sur ace from the necessities of its manufacture will accurately and 86 faithfully conform to the curvature or surface of the lens blank or lens to be polished.

The full nature of the invention will be understood from the accompanying 'drawings and the following description and claims:

In the drawings, Figure 1 is a central section through a lens block and rough ground lens blank secured thereon, and a sheet of lead placed thereon. Fig. 2 is a perspective view. of a tool holder coated with cement. Fig.3 is a section through the lens block, lens, sheet of \lead and cement and tool holder, all pressed together. Fig. 4 is a perspective view of the finished tool for fine grinding and polishing made by this process.

In the art of making ophthalmic lenses, particularly toric lenses, by employing the or polishing sur-' process'herein set forth, the lens 10 is rough ground while secured to a lens holder 11. The blank from which the lens is ground is secured to such lens holder by reason of the face of the lens blank coining in direct contact-with an annular beveled surface 12 of the lens block, andthe lens block is preferably of slightly less curvature than the surface of the lens or lens blank, so that the lens blank will be slightly spaced away from the lens block in the central part thereof and the lens blank and lens are secured to the block by a small body of cement 13, as shown in Fig. 1. vThe manner of mounting the lens blank on the lens block for rough grinding, however, is relatively immaterial to this process and invention, as it is applicable regardless of how the lens is secured to'the lens block while being rough 7 ground.

After the lens has been rough ground, it must be fine ground and polished, and to that this process relates, and the tool' pro duced by the process may be employed either for fine rinding or for polishing. The surface of t e lens is by the rough grin ing heretofore described. The fine grinding and polishing do not as a rule materially modify the generated surface of the lens and preferably should not modify it. Therefore, the tool for fine grindin or polishing should have a polishing sur ace which conforms exactly to the lens surface to be treated. In order to produce this result in a very simple and accurate manner this process was invented.

In th'efirst place a sheet of lead 15or other flexible abrading or polishing material is placed on the ground or previously generated surface of the lens blank and pressed tightly thereon so that it will be given a shape exactly corresponding to the lens.

In the next place a layer of cement 16 is spread over the face of a tool holder 17 and then the cemented faceof the tool holder is brought against thesheet of lead and the lens blank and lens holder 11 coaxially and subjected to pressure so that the sheet of lead'will adhere to thecement on the tool holder 17 and have an abrading or polishing surface exactly corresponding to the generated surface of the lens blank. This is illustrated in Fig. 3. Then the fine grindenerated and determined sheet of lead or other flexible material secured thereto.

When the device shown in Fig. 4 is usedfor fine grinding, the lens holder with the lens blank thereon and the fine grinding tool are relatively rotated simultaneously according to the usual practice so as to fine grind the lens. This greatly cheapens the process of fine grinding and. also insures no change whatever of the curvature of the lens from that generated by the grinding machine. 1 This last feature is of great value.

The next step in the process of making the lens is to polish the lens and for this purpose a polishin tool is made in a manner similar to the ne grinding tool above described and shown in Fig. 4, excepting that insteadof a flexible sheet of lead or like abrading material being first shaped over the lens, a sheet of felt or like flexible polishing material is merely placed on the lens blank and adhered to the tool holder in substantially the same manner as above described by bringing the cement covered face I of the tool holder into engagement therewith under pressure so that the felt or like flexible polishing material will conform to the shape of the lens, so that it, during the polishing of the lens blank,-will not to any extent change the curvature of the, surface generated on the lens in the rough grinding operation. With this process neither the lead sheet nor the cement or pitch need be of uniformthickness as the pressure on them of the lens blank and the tool willcause the material added to the tool to be substantially of uniform thicknes'sand atany rate to have an'operative grinding-or polishing surface which conforms exactly to the curvature'of the surface to be, ground or polished. Also the lens blank in the process of formingthis tool is brought into contact only with the sheet of leador other flexible sheet which are not adhesive or sticky so that they will not stick to the.,lens blank, but on the contrary the pressure on the lead sheet of the lens blank will tend to make its surface smooth.

The invention claimed is. Y

' The rocess of making a tool for treating the sur ace of an ophthalmic lens after such surface has been generated which process includes placing a flexible sheet of'material on the surface of the lens which is to be subsequently treated, forming the face of a tool holder with substantially the reverse with a layer of cement, and bringing the cement on the face of the tool holder into engagement with the sheet of material on the covered face of the lens under pressure, whereby the flexible sheet of material will adhere to'the tool and have the exact sha e of the surface of the lens which is to be su sequently treated.

Ina witness whereof, afiixed our signatures.

LUCIAN W. BUGBEE. IAUCIAN W. BUGBEE. JR.

we have hereunto 

